Elongated connecting elements, such as rods, plates, tethers, wires, cables, and other devices have been implanted along the spinal column and connected between two or more bone anchors engaged between one or more spinal motion segments. Such connecting elements can be positioned in the respective bone anchors with a top-down approach, a side-to-side approach, or a serial, endwise approach. In any event, it is desirable to securely engage the connecting element in the bone anchor to maintain the spinal stabilization effect provided by the connecting element when engaged between the bone anchors.
Typical implant and connection systems include several pieces, which commonly are useful and may be associated with only specific other pieces. Bone screws, hooks, and clamps are well known as spinal bone anchors, which are connected or adjoined to a particular bone as a connection between the bone and the connection system which can include an elongated connecting element that provides a support and/or stabilizing member. In such a system, a series of two or more bone anchors may be inserted into two or more vertebrae to be instrumented. A connecting element is then placed within or coupled to the bone anchors with engaging members, and the engaging members are tightened. In this way, a supporting structure is secured to the vertebrae, with the connecting element providing the support that promotes correction or healing of the vertebral malformation or injury. However, during surgery the connection of the connecting element to the bone anchors can be frustrating and time consuming for the surgeon due to intricacies involved in positioning the engaging member into the patient and securing it to the bone anchor. For example, the potential for cross-threading a set screw or nut to the bone anchor exists when threadingly coupling engaging members to the bone anchor. Also, the handling of small, intricate components for placement within the body during surgery and for interconnection with the bone anchor can also be time consuming and require great care on the part of the surgeon. Therefore, it would be desirable to minimize the number of components that are separately positioned within the body of the patient during surgery and to simplify the interaction between the various components.